Aim of this student research project was to develop an Aluminium Oxide (Al2O3 ) ALD process from trimethylaluminum (TMA) and Ozone in comparison of two shower head designs. Then studying the detailed characteristics of Al2O3 ALD process using various measurement techniques such as Spectroscopic Ellipsometry (SE), x-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM). The real-time ALD growth was studied by in-situ SE. In-situ SE is very promising technique that allows the time-continuous as well as time-discrete measurement of the actual growth over an ALD process time. The following ALD process parameters were varied and their inter-dependencies were studied in detail: exposure times of precursor and co-reactant as well as Argon purge times, the deposition temperature, total process pressure, flow dynamics of two different shower head designs. The effect of varying these ALD process parameters was studied by looking upon ALD cycle attributes. Various ALD cycle attributes are: TMA molecule adsorption (Mads ), Ligand removal (Lrem ), growth kinetics (KO3 ) and growth per cycle (GPC).

Aim of this student research project was to develop an Aluminium Oxide (Al2O3 ) ALD process from trimethylaluminum (TMA) and Ozone in comparison of two shower head designs. Then studying the detailed characteristics of Al2O3 ALD process using various measurement techniques such as Spectroscopic Ellipsometry (SE), x-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM). The real-time ALD growth was studied by in-situ SE. In-situ SE is very promising technique that allows the time-continuous as well as time-discrete measurement of the actual growth over an ALD process time. The following ALD process parameters were varied and their inter-dependencies were studied in detail: exposure times of precursor and co-reactant as well as Argon purge times, the deposition temperature, total process pressure, flow dynamics of two different shower head designs. The effect of varying these ALD process parameters was studied by looking upon ALD cycle attributes. Various ALD cycle attributes are: TMA molecule adsorption (Mads ), Ligand removal (Lrem ), growth kinetics (KO3 ) and growth per cycle (GPC).:List of abbreviations and Symbols ........................XII Lists of Figures and Tables ...................................XVIII 1 Introduction .......................................................1 I Theoretical Part ..................................................3 2 Alumina in electronic industry ............................5 3 Atomic Layer Deposition ....................................7 3.1 History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3.2 Process definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3.3 Benefits and limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3.4 ALD growth mechanism of Aluminium oxide from TMA/O 3 . . . . . . . . 9 3.5 Growth kinetics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 3.6 Comparison of TMA/O3 and TMA/H2O – A literature survey . . . . 14 4 Spectroscopic Ellipsometry .....................................................17 4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 4.2 Measuring Principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 4.3 Fitting and models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 4.4 Advantages and limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 5 X-Ray Photoelectron Spectroscopy ..............................................25 5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 5.2 XPS mechanism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 5.3 XPS analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 5.4 Advantages and limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 6 Atomic Force Microscopy .............................................................29 II Experimental Part ......................................................................31 7 Methodologies ............................................................................33 7 .1 Experimental setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 7 .2 ALD process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 7 .3 Experiment design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 7 .4 Spectroscopic Ellipsometry . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 7 .4.1 Tool and software . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 7 .4.2 Data acquisition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 7 .4.3 Data evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 7 .4.4 Post processing of data . . . . . . . . . . . . . . . . . . . . . . . . . 41 7 .4.5 Sources of errors in SE . . . . . . . . . . . . . . . . . . . . . . . . . 43 8 Results and discussion ..........................................................47 8.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 8.2 Kinetic ALD characteristic curves . . . . . . . . . . . . . . . . . . . . . . . . 48 8.2.1 TMA exposure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 8.2.2 Argon purging after TMA exposure . . . . . . . . . . . . . . . . . . . 50 8.2.3 Ozone exposure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 8.2.4 Argon purging after ozone exposure . . . . . . . . . . . . . . . . . . 52 8.3 Impact of process parameters on characteristic ALD growth attributes and film properties . . . . . . . . . .. . . . . . . . . . . . . . . . 53 8.3.1 Total process pressure . . . . . . . . . . . . . . . . . . . . . . . . . . 53 8.3.2 Ozone flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 8.3.3 Deposition temperature . . . . . . . . . . . . . . . . . . . . . . . . . 56 8.4 Reproducibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 9 Conclusions and outlook .......................................................63 References ...............................................................................68 III Appendix .............................................................................77 A Reference temperatures and ozone flow.............................. 79 B Process parameters ..............................................................81